Emails: Lei Zhao (leizhao2016@163.com), Feng Chen (fengchen@henau.edu.cn)

Low temperature as one of the most important abiotic stresses has caused serious wheat production loss worldwide. Here, we reported genetic identification and functional analysis of the Cold Controlling 1 (TaCOCO1) gene affecting cold tolerance in wheat. TaCOCO1-overexpressed transgenic wheat plants significantly enhanced cold tolerance, whereas EMS mutant and CRISPR/Cas9-mediated knockout plants were more sensitive to cold response, indicating that TaCOCO1 positively regulates cold tolerance in wheat.

Interaction analysis showed that TaCOCO1 strongly interacted with TaMYB4 and reduced the protein level of TaMYB4 during co-expression. We subsequently found that the BSMV-mediated silenced wheat plants and EMS mutants of TaMYB4 possessed significantly increased wheat cold tolerance. Furthermore, we revealed that TaMYB4 bound to the promoter of TaCBF12d to repress its expression, and BSMV-mediated TaCBF12d-silenced wheat plants possessed significantly decreased wheat cold tolerance.

Luciferase complementation assay showed that TaCOCO1 alleviated the inhibition of TaMYB4 on the transcriptional activity of TaCBF12d. Therefore, TaCOCO1 regulated wheat cold tolerance possibly through mediating TaCBF12d expression.

This study offered a new insight into the molecular mechanism of wheat cold tolerance involved in CBF pathway, and also provided valuable genes for the improvement of cold tolerance in wheat breeding program.